Adding several textures to subdivided/leveled plane
It has been a while, but in case other people are looking for a solution:

To see UV mapped textures in the viewport set to GLSL shading and textured view.
You will also need to have some lighting in your scene or in the material setting enable 'shadeless'.

I had no light source in my blend project, which explains why everything went black. This is where enabling 'shadeless' for the material comes in handy.



credits: "Richard Marklew - blenderartists.org"